In general, there are many systems that require a first element to be "tuned" with respect to a second element in accordance with a predetermined parameter relating the two. For example, a radio receiver needs to be properly tuned to an RF signal in order to capture a particular transmitted signal. In the field of astronomy, star tracking is accomplished by controlling the image centering using a photomultiplier.
In the field of optical component assembly, it is important that the maximum optical signal power be coupled between the components. In this case, "tuning" relates to the alignment of a first piece part to a second piece part. In most conventional optical component assembly systems, a first component is often affixed to an x-y-z alignment table and a second component is held in a fixed position. The first component is then moved in all three axes, relative to the second component, until maximum coupled power is achieved. Practical, as well as experimental, limitations exist in the conventional methods of obtaining this alignment, as well as with the other "tuning" examples mentioned above. For example, "backlash" associated with the movement of the alignment table has been found to hinder the alignment process.
In more general situations, the need frequently arises where a parameter is changed (for example, relative position of two components in an optical subsystem) and a figure of merit (for example, coupled power between the components) is measured. There are many arrangements for recording the figure of merit and using the recorded data to determine when the parameter has been optimized. What is needed in the industry is a robust technique that takes into consideration the problem of backlash, as well as other sources of "noise" in the tuning process.